Electrically-operated water heater



Patented Jan. 14, 1939 UNITED STATES PATENT OFFICE ROBERT L, SHRINER, 0FWEEHAWKEN, NEVL JERSEY, ASSIGNOR TO SOT, HI LOU NOVAK, AND ROBERT L.SHRINER DOING BUSINESS ENGINEERING (10., OF NEW YORK, N. Y.

WILLIAM FEIN- AS INNOVATION ELECTRICALLY-OPERATED VJATER HEATERApplication filed April 14,

This invention relates to heating devices and more particularly isdirected to an electric heating system and unit for water heaters Oneobject of the invention is to provide an improved electrically operatedsystem for water heaters in which there is an etficient irculation ofwater.

A further object of the invention is to provide an improved heatingsystem for water heaters in which there is ethcient heat transference ata minimum of heat losses.

Another object of the invention is to, provide an electrically operativeheating system and apparatus of the character, described comprisingfewand simple parts, which shall be relatively cheap to manufacture, andwhich may be readily disassembled for inspection and replacement andrepair of defective parts.

Still another object of the invention is to generally improve waterheaters of the character described to render same practical. efiicientand economical in operation to a high degree.

Otl er objects of this invention will in part be obvious and in parthereinafter pointed out. i

Certain features herein shown and described are shown, described andclaimed in my co-pending application Serial Yo. 159,251 tiled J an. 6,1927, and accordingly are not claimed herein.

With the above exception, the invention accordingly consists inthefeatures of construction, combinations of elements, and-ar rangcment ofparts which will be exemplified in the construction hereinafterdescribed, and of which the scope of application will be indicated inthe following claims.

in the accompanying drawing, in'which is shown one of the variouspossible illustrative embodiments of this invention,

Fig. 1 is a cross-sectional view of an electrically operated waterheater embodying the invention. 1

Figs. 2 and 3 are cross-sectional views taken on lines 22 .and 33 inFigs. 1 and 2, respectively;

'Fig. a is a diagrammatic view showing A circular base plate 16 1927.Serial No. 183,709.

various switch connections of the heater element to the electric supplysource.

Referring in detail to the drawing, 10 denotes an electrically operatedwater heater constructed to embody the invention. Said heater is seen tocomprise a casing 11 mounted upon a standard 12 and provided with asuitable heat insulating covering 13 formed of magnesia, asbestos, feltor the like mate-rial applied thereovcr in any suitable well knownmanner. The upper end of the casing 11 is provided with a top closure orhead 14 which is connected to the casing by a lap joint 15 being eitherriveted or welded or otherwise suitably secured to make a water-tightjoint.

is mounted at a substantial distance from the bottom of the casing 11for partitioning the water receiver or reservoir A above the plate 16from the lower compartment B below the same. Said plate 16 has aperipheral outturned edge portion 16 which lies in-close contact withthe casing 11 and may be riveted or welded thereto to provide awatertightjoint. 17 indicates an inlet pipe which admits cold water tothe receiver A from a suitable water supply source (not shown), and 18indicates an outlet pipe through wl 'ch the hot water is drawn to thereceiver. The pipes 17 and 18 are connected to the head 14 by means ofthe flange iittings 14 v which are joined to the head by suitable meanssuch as welding, rivets bolts or the like.

Mounted on the plate 16 to extend axially with respect to the casing 11is a tubular housing 19 provided with corrugations 19 extendingsubstantially the length thereof. Said casing forms a chamber C and issecured water-tight to the plate 16 by an outwardly turned flange 19'.The upper end of the housing is closed by means of a dished plate 20which is centrally perforated-for receiving a vertically extending pipe21 which extends axially through the housing 19. Pipes 22 spaced inparallel alignment with pipe 21 are provided for communicating with thereservoir A through the plate 16. Each pipe 22 detachably connects atone end with plate 16 by means of a union coupling 23, and the other endof each of said pipes 22 connects with a horizontally extending pipe 24which terminates in a faucet 25 for draining the reservoir A. The pipe21 is joined at its lower end through a coupling 26 with the pipe 24 bya T-fitting 27, the upper end of the pipe 21 being open and incommunication with the reservoir A. The pipe 21 is preferably formed oftubing and may be made with a helical ridge 21 in its wall structure asshown in Figs. 1 and 2. Mounted to extend above the end of the pipe 21is a battle plate 28 which is carried by a rod 29 suitably secured tothe upper end of the pipe 21 by a crow-foot or hicky 30 in thewell-known manner.

Referring now to Figs. 2 and 3, the electric heater unit H is seen tocomprise an upper head plate 31 and a lower plate 32 both of which maybe shaped to correspond to the cross-section of the housing 19 and areheld in fixed relation with respect to each other by stay-bars 33 andnuts 34. An intermediate insulating plate 35 is mounted in spacedrelation to the plate 32 and is held in position by said stay'bars 33and, nu'ts 36. Mounted between the plates 32 and 35 at equal intervals,preferably in concentric relation, are four insulating tubes 37. Passingthrough the plate 32 and electrically insulated to extend into thetube'are the screw members 38, each of which has a head 38. The latteris adapted to be adjusted longitudinally of the tubes 37 by rotatingsaid member 38. A dished spring 39 rests on each of the heads 38 and isfirmly secured to the lower ends 4O of plunger 40 which is adapted toslide through the insulating plate 35. The upper end of each plunger isformed with a cup-shaped portion 40 and is adapted to support the lowerends of the resistance elements 41. Mounted on the upper plate 31opposite each of the-cup portions 40 and in alignment therewith are thecup members 42. Each of the latter is adapted to receive the upper endsof one of the resistance elements 41. In the embodiment of the inventionhere shown four heater elements are employed which are adapted to beconnected in series and. in series parallel relation, the upper ends ofthe resistance elements being interconnected by means of connectors 43.The electrical heater unit H is thus seen to form a unit as shown inFig. 3 which is positioned interiorly of the housing 19 and is removablyheld in place by a supporting head 44. The latter is provided with aflange 44 which is detachably secured against the housing flange 19 andthe plate 16 by the bolts 45, and is formed with a passage 44 throughwhich thejelectric heater unit extends into the chamber C, as shown Fig.1.

The plates 31, 32 and 35 of the heater unit are provided with centrallyaligned openg 3 32a nd esp ctive y, wh h f rm an axial passage forreceiving the pipe 21 so that the resistance elements are disposed inclose relation between the pipe 21 and the housing 19 as shown in Figs.land 3. Mounted in the lower compartment B under the reservoir A is theswitch or junction box 46 through which pass conductor leads 47 forconnecting the resistance elements of the heater with the electric powersupply source (not shown).

48 indicates a conventional type of thermostat which may be installed toextend through the casing 11 into the reservoir A and is designed toregulate the operation of the heater in accordance with the temperatureof the water. The thermostat used in the installation described aboveforms no part of the invention and any of the thermostats well known inthe art may be used. A conduit 49 mounted to extend through the covering13 serves to carry the conductor wires 47 which connect the heatingsystem tothe source of power.

A switch 50 is mounted on the box 46 and controls the power supply tothe heater unit. Said switch may be of any standard construe tion and isadapted to selectively connect in circuit the pairs of resistanceelements either in series or series-parallel as is clearly showndiagrammatically in Fig. 5. Thus in the position of the switch shown atW, the circuit is open. In the position X, the resistance elements areconnected in series-parallel. In position Y, only one pair of resistanceelements are connected in circuit, the other two being shunted out ofcircuit, and in the position shown at Z, the elements are all connectedin series. As shown in Fig. 1, the switch 50 may be of the rotary typeand controls the circuit by rotation of a key 50 for consecutivelypositioning the switch connections to 'oin the pairs of resistanceelements as shown at X, Y and Z in Fig. 4 in the well understood manner.7

The operation of the apparatus will now be clear, The cold water entersthrough the pipe 17 and fills the reservoir A. Water also fills pipes21, 22 and 24. When the temperature of the water in the reservoir Afalls to a certain predetermined point, the thermostat starts theoperation of the heating unit on closing the electric circuit throughmanipulation of the switch key 50*. Current then flows through the leads47, the screw members 38, the heads 38*, the springs 39, the plungers40, the cup-shaped portions 40*, and the resistance elements 41. Ifdesired, a flexible jumper 51 may be secured to form a shunt circuitbetween each head 38 and its contacting plunger 40 so that practicallyall the curre passes th ugh he jumpe 51 r r than through the springs 39.Each jumper 1 may have nsu a ng beads 5. Strung t on and has one endanchored to the plunger 40 by means of a washer 51 secured over the sp ig 3 the the and o th ju p being locked under a nut 52 threaded on thescrew member 38, as is clearly shown in Fig. 3.

By means of connectors 48, a series path for the current is providedthrough the pairs of resistance element 41. Thus the current flowsthrough said leads 47 and resistance elements sucessively. WVith saidelements connected to the power circuit, they are heated to a mediumtemperature when the switch is in the position shown at Z in Fig. 5, andto a higher temperature when the switch is in the position correspondingto X and Y in Fig. 5. The heat developed by these elements istransmitted to the pipe 21 by both radiation and conduction. l/Vhile theheat is transferred at maximum intensity to said pipe, it is alsotransferred to the housing 19 and heats the water in the res ervoir A.It should be noted that the heater elements are brought in very closeproximity to the walls of the pipe 21 and housing 19 so that the heat isreceived and transmitted through said walls with a minimum of heatlosses.

The circulation of the water results from the well known physical factthat the density of the water is greater at lower than at highertemperature. The circulation of the water takes place in the followingcourse:

The cold water sinks in the pipes 22 and 24 and passes through theT-fitting 27 into the pipe 21 where the temperature of the water israised by the heat received from the unit H. This, of course, causes thehot water to rise and consequently the cooler water falls behind, whereit is in turn raised in temperature until it passes out of the upper endof the pipe 21 into the reservoir A. In order to facilitate renderingmore eflicient the heat transfer between the water and the hot surfaceof the housing 19, the latter as has been described above is corrugatedlongitudinally so as to present a large heat radiating surface. and thedished plate 20 of the housing 19 is extended beyond the corrugated wallof the housing to break up the water stream and to give it a stirringaction in the reservoir A.

lVhen the water in the reservoir has reached the upper limit of thetemperatures for which the thermostat is set, the latter operates toopen the main circuit thus shutting off the current supply. The actionof the heater is thereby rendered entirely automatic and hot water ofany desired temperature within the usual heater range may be withdrawnthrough the pipe 18. The switch 50 when set as shown at 1V in Fig. 4renders the heating system entirely inoperative, and the switch settingsshown at X, Y and Z permit the control of the heating to take place at aslower or more rapid rate, as desired, as will be readily understood.

In order to simplify the assembly of the apparatus and also thereplacement of the parts such as the resistance elements, the chamber Bis made of suflicient size to permit the vitals of the heater unitto bedropped sufiiciently to give ready access to its parts. Thus, when it isdesired to inspect or replace a resistance element the water need not bedramed from tion of replacing one of these elements is eX- tremelysimple, it merely being necessary to lower the screw member 38 to permitremoving the element from the plunger cup portions 40*.

lVhen first installing the device or when putting it in service after ithas not been used for some time, filling of the reservoir A with coldwater may cause the interior wall of the housing 19 to condense moisturefrom the surrounding air due to the well known phenomenon commonly knownas sweating. Such moisture will accumulate in drops, run down the sidewall of the housing 19 and lodge between the current carrying parts ofthe heating unit H and the housing, as for example between the outsideof the cup members and the adjacent wall portion of the housing 19, thusgrounding the circuit to the housing 19 through said accumulatedmoisture. On evaporation of said moisture, arcing will result which willperforate the housing and cause it to leak. To overcome this possibleserious objection, a layer of suitable absorbing material 54, such assheet asbestos is inserted about the periphery of the plate 35, saidlayer being extended up along the side of the housing beyond the cupportions 40 so that any accumulation of moisture that runs down the sideof the housing is caught and absorbed by said material 54. The latter isdried on operating the heater unit H witl1- out the least injury ordamage to the device.

It will thus be seen that there is provided a device in which theseveral objects of this invention are achieved, and which is welladapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention,and as various changes might be made in the embodiment above set forth,it is to be understood that all matter herein set forth or shown in theaccompanying drawing is to be interpreted as illustrative and not in alimiting sense.

Having thus described my invention, 1 claim as new and desire to secureby Letters Patent 1. In a water heater of the class described, anelectrical heating unit comprising a plurality of spaced resistanceelements connected in electric circuit, and spring means for demountablysecuring said individual elements in said circuit, said means includinga socket member for receiving one end of each of said elements,resilient means secured to said socket member, and means for adjustingthe tension of said resilient means.

2. In a Water heater of the class described, an electrical heating unitcomprising a plurality of spaced resistance elements connected inelectric circuit, and means for demounta-bly securing said individualelements in said circuit, said means including a socket member forreceiving one end of each of said elements, resilient means secured tosaid socket member, and means for adjusting the tension of saidresilient means, said adjusting means comprising a member having a headportion supporting said resilient means, and a screw threaded shankportion extending therefrom.

3. In a Water heater of the class described, an electrical heating unitcomprising a plurality of spaced resistance elements connected inelectric circuit, and means for demountably securing said individualelements in said circuit, said means including a socket member forreceiving one end of each of said elements, resilient means secured tosaid socket member, and means for adjusting the tension of saidresilient means, said adjusting means comprising a member having a headportion supporting said resilient means, and a screw threaded shankportion extending therefrom, and jumper means for connecting said shankportion and said socket member.

In testimony whereof I affix my signature.

ROBERT L. SHRINER.

